. Biology of the laboratory mouse. Mice as laboratory animals; Mice; Animals, Laboratory; Mice. 50 BIOLOGY OF THE LABORATORY MOUSE it, the sides of the U are Ukewise brought into approximation and fused together in the mid-ventral Une. The endocardium is thus transformed from a U-shaped structure into a single tube. At the three somite stage (in the rat) the different regions of the heart are not clearly set apart, though a slight constriction serves to mark the boundary between the atrium and the ventricle. As a result of subsequent foldings of the endocardial tube the different regions of th
. Biology of the laboratory mouse. Mice as laboratory animals; Mice; Animals, Laboratory; Mice. 50 BIOLOGY OF THE LABORATORY MOUSE it, the sides of the U are Ukewise brought into approximation and fused together in the mid-ventral Une. The endocardium is thus transformed from a U-shaped structure into a single tube. At the three somite stage (in the rat) the different regions of the heart are not clearly set apart, though a slight constriction serves to mark the boundary between the atrium and the ventricle. As a result of subsequent foldings of the endocardial tube the different regions of the heart are clearly differentiated (Fig. 31). Internal carotid artery Aortic arch I Allantois Omphalomesenteric artery. Atrium Omphalomesenteric vein Vitelline arteries Yolk-sac Fore-gut Dorsal aorta Hind-gut Fig. 31.—Diagram of the circulatory system in an 8 day 10 hour, 10 somite embryo. The head and tail folds of this embryo have begun to turn but there is as yet no turning in the mid-trunk region. Traces of the allantoic veins are present but are not shown as they do not yet form a continuous channel. (X64.) Blood vessels.—In ten somite embryos, still in the process of turning, a number of blood vessels have become established (Fig. 31). The dorsal aorta at this stage is a paired vessel running the length of the trunk. It connects anteriorly with the heart by way of the aortic arches and the ventral aorta. Posteriorly its two halves fuse at the caudal extremity of the hind- gut to form the single, median, omphalomesenteric artery. This runs cephalad for a short distance ventral to the hind-gut and then turns away from the embryo towards the inner surface of the yolk-sac on which it spreads out into a network of capillaries. These capillaries are derived from. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original
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Keywords: ., boo, bookcentury1900, bookcollectionbiodiversity, booksubjectmice
